1. Talking into an echo chamber.
So it's you and your buddy on the mic and it's definitely natural you will agree on some things (most things? I don't know your relationship.) But, as a listener, it's not really all that productive to listen to two people agree for an hour straight. You probably remember from the SATs or something that persuasive arguments include some counterpoints, debunked, and a new perspective or two. Consider that while structuring your conversation and while researching guests.
2. Leaning too much on your friends as your guests.
This goes with point #1 -- a lot of new podcasters rely heavily on close friends for their first couple interviews. Totally understandable when your show doesn't have any street cred. This is also heavily genre-specific and might be totally fine with a comedic podcast. I've just got a couple questions, though. Is your buddy actually the best voice for their perspective? Are they an 'expert' or what's their experience level with the topic? Will you be able to listen to them objectively without filling in the gaps with your own knowledge? By that I mean, will a third-party listener understand what they're saying like you do? By all means, have some buddies on your show, but try to challenge yourself by branching out when you're ready and remember to fill in those gaps out loud.
3. Over-clarifying your questions and/or giving your guest the answers.
I think this is probably a nervous thing. You asked a question and now you're worried that you didn't make any sense. Maybe you're worried it's too personal or not specific enough, so you start listing off potential answers (like I just did? whoops). Perhaps one way to get around these nerves is by writing down as many questions as you can before the interview and asking a peer if they make sense, just so you're not worried about it in the moment. Otherwise, ask the question, sit back, let the guest respond. If they ask for more clarification, give it to them, but, otherwise, you're just backing them into a corner or getting a less authentic response than you could've had.
4. Not giving your listeners enough credit.
"I don't think listeners will understand because it's pretty complicated," "I'm sure your listeners don't care about this," etc. Ok! If it doesn't make sense we can cut it in post! I'm not sure if these kinds of comments are coming from a self-conscious place (being unsure if you're explaining correctly) or if you just don't know who your audience is, but I promise your listeners are trying to learn and understand if they're tuning in. I love it when hosts know their audience. While editing Nick Carrier's Best You Podcast I recall Nick saying something like, "I know my listeners are ambitious, and they like working to meet their best self, so..." Yes! Of course they are, Nick! They're listening to your podcast about becoming their best self! I'm sure all of his listeners heard that and felt seen. Take a lesson from Nick and remember who your audience is if you're going to talk about them in your show. Anything negative or condescending almost feels like the host is talking about you behind your back!
5. Not prepping your guests.
I get it, you don't want a cookie-cutter answer, you want an off-the-cuff brilliant gold nugget or a thought-provoking moment. There is a time and place for those jaw-dropping questions, and of course your conversation, ideally, will flow naturally...but there are certain questions that are just awkward if they haven't been prepared. E.g. If you're looking for statistics and facts that they might not know off the top of their head, do everyone a favor and let them bring a cheat sheet to the interview. Guests will also feel more confident going into the interview if they know roughly what you want to talk about. Just jot down a couple key questions and topics and email them over to your guest a couple days in advance.